A device, such as a mobile device and a camera, having a battery pack is configured to fix a battery to be removable. The battery pack is housed in a housing chamber defined in a body case of the device and is fixed to the body case in the housing chamber not to be removed easily.
A fixing structure that fixes the battery pack is known to retain the battery pack by the body case such that the body case receives a force applied thereto in a direction in which the battery pack comes out of the body case (refer to Patent Literature 1). Alternatively, a cover is mounted to the body case to retain the battery pack, and the body case holds the cover. When retaining the battery pack by the cover, the cover prevents the battery pack from coming out of the body case.
However, the battery pack may slip on the body case or on the cover when an angle between the battery pack and the body case or the cover at a position where the battery pack is in contact with the body case or the cover is small while the battery pack or the cover is attached to the body case. Therefore, a direction in which the body case receives the force applied thereto from the battery pack when the battery pack comes out of the body case in a removing direction, i.e., a direction in which a stopper of the battery pack receives a force, crosses the removing direction at a right angle or at a large angle preferably.
Then, according to the fixing structure, the body case has a groove, which has an L-shape in cross section, and the battery pack or the cover has a protrusion. The protrusion fits into the groove, whereby the body case receives the force applied thereto from the battery pack or the cover in the removing direction.